I usually play with 2 players, but last night I decided to try my hand at single player and quickly chucked together the following deck. It's a very basic tactics/spirit deck and doesn't contain 'splashes' of non-hero spheres (trying to avoid cards I feel I rely on too much e.g. steward of gondor). I've only played 'Into the Pit' and 'The Seventh Level' so far and managed to beat them both on the first attempt.. which surprised me because I didn't build the deck around any particular theme or strategy, and I had both Watchful Eyes attached to Glorfindel and Beorn the majority of the time but the deck still coped (it was nice not having rely on Miner of the Iron Hills for once - I've only ever really played Khazad-Dum with Dwarves). I just wanted to try out Beorn . I have very little single player experience so any improvements/suggestions are very welcome!

HEROES (starting threat 26):

Beorn
Glorfindel (Spirit)
Eowyn

Deck (50 cards):

ALLIES (20)

Vassal of the Windlord x3
Gondorian Spearmen x3
Trollshaw Scout x3
Imladris Stargazer x2
Zigil Miner x2
Arwen Undomiel x2
Northern Tracker x2
Gandalf x2 (Core)
Gandalf x1 (Over Hill and Under Hill)

ATTACHMENTS (16)

Horn of Gondor x1
Blade of Gondolin x2
Rivendell Blade x3
Light of Valinor x3
Miruvor x3
Ancient Mathom x3
Unexpected Courage x1

EVENTS (14)

Unseen Strike x2
Feint x2
Elrond's Counsel x3
A Test of Will x2
Hasty Stroke x2
Dwarven Tomb x1
Stand and Fight x2

whoops just noticed the 'cannot have attachments' text on beorn… does this include encounter cards too?

I would say Yes to not able to attach encounter cards to Beorn. In the rule insert of OHaUH, there is an example of not able to attach Sack card to Beorn, so I think it is the same for encounter cards.

Beorn can't have attachments of any kind, including treacheries that turn into attachments.

I think this deck could use a few more allies over attachments. I go by 50% allies.